We saw that the resistive gain in motive what they lose in adaptability; we may add that in a sense the unstable gain in adaptability what they lose in motive. Thus we see society cleft by the instinctive qualities of its members into two great classes, each to a great extent possessing what the other lacks, and each falling below the possibilities of human personality. The effect of the gradual increase of the unstable in society can be seen to a certain extent in history. We can watch it through the careers of the Jews and of the Romans. At first, when the bulk of the citizens were of the stable type, the nation was enterprising, energetic, indomitable, but hard, inelastic, and fanatically convinced of its Divine mission. The inevitable effect of the expansion of experience which followed success was that development of the unstable and sceptical which ultimately allowed the nation, no longer {60} believing in itself or its gods, to become the almost passive prey of more stable peoples. In regard to the question of the fundamental significance of the two great mental types found in society, a tempting field for speculation at once opens up, and many questions immediately arise for discussion. Is, for example, the stable normal type naturally in some special degree insensitive to experience, and if so, is such a quality inborn or acquired? Again, may the characteristics of the members of this class be the result of an experience relatively easily dealt with by rationalization and exclusion? Then again, are the unstable naturally hypersensitive to experience, or have they met with an experience relatively difficult to assimilate? Into the discussion of such questions we shall here make no attempt to enter, but shall limit ourselves to reiterating that these two types divide society between them, that they both must be regarded as seriously defective and as evidence that civilization has not yet provided a medium in which the average human mind can grow undeformed and to its full stature. GREGARIOUSNESS AND THE FUTURE OF MAN. Thus far we have attempted to apply biological conceptions to man and society as they actually exist at present. We may now, very shortly, inquire whether or not the same method can yield some hint as to the course which human development will take in the future.